diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/api.yml b/spiffworkflow-backend/src/spiffworkflow_backend/api.yml
index 764ba543f..84ada2341 100755
--- a/spiffworkflow-backend/src/spiffworkflow_backend/api.yml
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/api.yml
@@ -699,6 +699,12 @@ paths:
         description: The unique id of an existing process instance.
         schema:
           type: integer
+      - name: process_identifier
+        in: query
+        required: false
+        description: The identifier of the process to use for the diagram. Useful for displaying the diagram for a call activity.
+        schema:
+          type: string
     get:
       tags:
         - Process Instances
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py
index 1e85f7229..ac2e3200b 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/spec_reference.py
@@ -8,6 +8,10 @@ from marshmallow import INCLUDE
 from sqlalchemy import UniqueConstraint
 
 
+class SpecReferenceNotFoundError(Exception):
+    pass
+
+
 @dataclass()
 class SpecReference:
     """File Reference Information.
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py b/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py
index 52bb11715..019f4b648 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/models/task.py
@@ -118,6 +118,7 @@ class Task:
         form_schema: Union[str, None] = None,
         form_ui_schema: Union[str, None] = None,
         parent: Optional[str] = None,
+        call_activity_process_identifier: Optional[str] = None,
     ):
         """__init__."""
         self.id = id
@@ -129,6 +130,7 @@ class Task:
         self.documentation = documentation
         self.lane = lane
         self.parent = parent
+        self.call_activity_process_identifier = call_activity_process_identifier
 
         self.data = data
         if self.data is None:
@@ -187,6 +189,7 @@ class Task:
             "form_schema": self.form_schema,
             "form_ui_schema": self.form_ui_schema,
             "parent": self.parent,
+            "call_activity_process_identifier": self.call_activity_process_identifier,
         }
 
     @classmethod
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py b/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py
index c29cf2148..3a73098fd 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/routes/process_api_blueprint.py
@@ -65,7 +65,7 @@ from spiffworkflow_backend.models.process_model import ProcessModelInfo
 from spiffworkflow_backend.models.process_model import ProcessModelInfoSchema
 from spiffworkflow_backend.models.secret_model import SecretModel
 from spiffworkflow_backend.models.secret_model import SecretModelSchema
-from spiffworkflow_backend.models.spec_reference import SpecReferenceCache
+from spiffworkflow_backend.models.spec_reference import SpecReferenceCache, SpecReferenceNotFoundError
 from spiffworkflow_backend.models.spec_reference import SpecReferenceSchema
 from spiffworkflow_backend.models.spiff_logging import SpiffLoggingModel
 from spiffworkflow_backend.models.spiff_step_details import SpiffStepDetailsModel
@@ -1073,25 +1073,38 @@ def process_instance_report_column_list() -> flask.wrappers.Response:
 
 
 def process_instance_show(
-    modified_process_model_identifier: str, process_instance_id: int
+    modified_process_model_identifier: str, process_instance_id: int, process_identifier: Optional[str] = None
 ) -> flask.wrappers.Response:
     """Create_process_instance."""
     process_model_identifier = modified_process_model_identifier.replace(":", "/")
     process_instance = find_process_instance_by_id_or_raise(process_instance_id)
     current_version_control_revision = GitService.get_current_revision()
-    process_model = get_process_model(process_model_identifier)
 
-    if process_model.primary_file_name:
+    process_model_with_diagram = None
+    name_of_file_with_diagram = None
+    if process_identifier:
+        spec_reference = SpecReferenceCache.query.filter_by(identifier=process_identifier).first()
+        if spec_reference is None:
+            raise SpecReferenceNotFoundError(f"Could not find given process identifier in the cache: {process_identifier}")
+
+        process_model_with_diagram = ProcessModelService.get_process_model(spec_reference.process_model_id)
+        name_of_file_with_diagram = spec_reference.file_name
+    else:
+        process_model_with_diagram = get_process_model(process_model_identifier)
+        if process_model_with_diagram.primary_file_name:
+            name_of_file_with_diagram = process_model_with_diagram.primary_file_name
+
+    if process_model_with_diagram and name_of_file_with_diagram:
         if (
             process_instance.bpmn_version_control_identifier
             == current_version_control_revision
         ):
             bpmn_xml_file_contents = SpecFileService.get_data(
-                process_model, process_model.primary_file_name
+                process_model_with_diagram, name_of_file_with_diagram
             ).decode("utf-8")
         else:
             bpmn_xml_file_contents = GitService.get_instance_file_contents_for_revision(
-                process_model, process_instance.bpmn_version_control_identifier
+                process_model_with_diagram, process_instance.bpmn_version_control_identifier, file_name=name_of_file_with_diagram
             )
         process_instance.bpmn_xml_file_contents = bpmn_xml_file_contents
 
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py
index f972b672b..519510e72 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/git_service.py
@@ -46,18 +46,21 @@ class GitService:
 
     @classmethod
     def get_instance_file_contents_for_revision(
-        cls, process_model: ProcessModelInfo, revision: str
+        cls, process_model: ProcessModelInfo, revision: str, file_name: Optional[str] = None
     ) -> str:
         """Get_instance_file_contents_for_revision."""
         bpmn_spec_absolute_dir = current_app.config["BPMN_SPEC_ABSOLUTE_DIR"]
         process_model_relative_path = FileSystemService.process_model_relative_path(
             process_model
         )
+        file_name_to_use = file_name
+        if file_name_to_use is None:
+            file_name_to_use = process_model.primary_file_name
         with FileSystemService.cd(bpmn_spec_absolute_dir):
             shell_command = [
                 "git",
                 "show",
-                f"{revision}:{process_model_relative_path}/{process_model.primary_file_name}",
+                f"{revision}:{process_model_relative_path}/{file_name_to_use}",
             ]
             return cls.run_shell_command_to_get_stdout(shell_command)
 
diff --git a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py
index 46bd252b9..38c71715d 100644
--- a/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py
+++ b/spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_service.py
@@ -302,6 +302,11 @@ class ProcessInstanceService:
         else:
             lane = None
 
+        if hasattr(spiff_task.task_spec, "spec"):
+            call_activity_process_identifier = spiff_task.task_spec.spec
+        else:
+            call_activity_process_identifier = None
+
         parent_id = None
         if spiff_task.parent:
             parent_id = spiff_task.parent.id
@@ -319,6 +324,7 @@ class ProcessInstanceService:
             process_name=spiff_task.task_spec._wf_spec.description,
             properties=props,
             parent=parent_id,
+            call_activity_process_identifier=call_activity_process_identifier,
         )
 
         return task
diff --git a/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx b/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx
index 9a0495d1d..a575968bd 100644
--- a/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx
+++ b/spiffworkflow-frontend/src/routes/ProcessInstanceShow.tsx
@@ -1,6 +1,11 @@
 import { useContext, useEffect, useState } from 'react';
 import Editor from '@monaco-editor/react';
-import { useParams, useNavigate, Link } from 'react-router-dom';
+import {
+  useParams,
+  useNavigate,
+  Link,
+  useSearchParams,
+} from 'react-router-dom';
 import {
   TrashCan,
   StopOutline,
@@ -40,6 +45,7 @@ import { usePermissionFetcher } from '../hooks/PermissionService';
 export default function ProcessInstanceShow() {
   const navigate = useNavigate();
   const params = useParams();
+  const [searchParams] = useSearchParams();
 
   const [processInstance, setProcessInstance] = useState(null);
   const [tasks, setTasks] = useState<Array<object> | null>(null);
@@ -80,8 +86,13 @@ export default function ProcessInstanceShow() {
       const processTaskFailure = () => {
         setTasksCallHadError(true);
       };
+      let queryParams = '';
+      const processIdentifier = searchParams.get('process_identifier');
+      if (processIdentifier) {
+        queryParams = `?process_identifier=${processIdentifier}`;
+      }
       HttpService.makeCallToBackend({
-        path: `/process-instances/${modifiedProcessModelId}/${params.process_instance_id}`,
+        path: `/process-instances/${modifiedProcessModelId}/${params.process_instance_id}${queryParams}`,
         successCallback: setProcessInstance,
       });
       let taskParams = '?all_tasks=true';
@@ -98,7 +109,14 @@ export default function ProcessInstanceShow() {
         setTasksCallHadError(true);
       }
     }
-  }, [params, modifiedProcessModelId, permissionsLoaded, ability, targetUris]);
+  }, [
+    params,
+    modifiedProcessModelId,
+    permissionsLoaded,
+    ability,
+    targetUris,
+    searchParams,
+  ]);
 
   const deleteProcessInstance = () => {
     HttpService.makeCallToBackend({
@@ -179,11 +197,9 @@ export default function ProcessInstanceShow() {
       <Link
         reloadDocument
         data-qa="process-instance-step-link"
-        to={`/admin/process-instances/${
-          params.process_model_id
-        }/process-instances/${params.process_instance_id}/${
-          currentSpiffStep(processInstanceToUse) + distance
-        }`}
+        to={`/admin/process-instances/${params.process_model_id}/${
+          params.process_instance_id
+        }/${currentSpiffStep(processInstanceToUse) + distance}`}
       >
         {label}
       </Link>
@@ -471,19 +487,28 @@ export default function ProcessInstanceShow() {
       );
     }
 
+    if (task.type === 'Call Activity') {
+      buttons.push(
+        <Link
+          data-qa="go-to-call-activity-result"
+          to={`/admin/process-instances/${params.process_model_id}/${params.process_instance_id}?process_identifier=${task.call_activity_process_identifier}`}
+          target="_blank"
+        >
+          View Call Activity Diagram
+        </Link>
+      );
+    }
+
     if (canEditTaskData(task)) {
       if (editingTaskData) {
         buttons.push(
-          <Button
-            data-qa="create-script-unit-test-button"
-            onClick={saveTaskData}
-          >
+          <Button data-qa="save-task-data-button" onClick={saveTaskData}>
             Save
           </Button>
         );
         buttons.push(
           <Button
-            data-qa="create-script-unit-test-button"
+            data-qa="cancel-task-data-edit-button"
             onClick={cancelEditingTaskData}
           >
             Cancel
@@ -492,7 +517,7 @@ export default function ProcessInstanceShow() {
       } else {
         buttons.push(
           <Button
-            data-qa="create-script-unit-test-button"
+            data-qa="edit-task-data-button"
             onClick={() => setEditingTaskData(true)}
           >
             Edit